A stent is an example of a collapsible medical device used, for example, in the treatment of diseased body lumens. A stent is generally a longitudinal tubular device formed of biocompatible material, which may be useful to open and support various body lumens. For example, stents may be used in body vessels, such as in the coronary or peripheral vasculature, an esophagus, a trachea, bronchi, a colon, a biliary tract, a urinary tract, a prostate, a brain, as well as in a variety of other locations in the body. Collapsible medical devices may be implanted within a vessel to open and/or reinforce collapsed or partially occluded portions of the vessel lumen. While stents are foreign objects to the human body, they may be designed to remain within a body lumen for prolonged periods or even indefinitely.
A stent may have an open flexible construction that may allow the stent to be inserted through curved vessels. Furthermore, this construction may allow the stent to be configured in a radially compressed state during delivery and/or implantation. Once properly positioned adjacent the damaged vessel, the stent may be radially expanded so as to support and conform to the vessel wall. Radial expansion of the stent has been accomplished by inflation of a balloon attached to the stent. Some stents foreshorten when radially expanded and get longer when radially contracted. Some stents are self-expanding that radially expands it once deployed. Super-elastic materials and metallic shape memory materials have been used to form stents.
On occasion, it may be useful to retrieve or reposition a stent previously deployed in a body lumen. For example, a stent may be relocated during deployment or after deployment for any of a variety of reasons. For example, a stent may be relocated and/or removed after a procedure that calls for only temporary use of the stent.
Deployed stents have been removed from body lumens by capturing a proximal end of the stent with a tool, such as a biopsy forceps or other snare, and then pulling proximally to withdraw the stent. One problem with this method is that pulling or pushing a fully radially expanded stent through a body lumen can damage surrounding tissue and the stent itself.
There is a need for a reliable and effective apparatus, system, and method for manipulating, removing, and/or repositioning a collapsible medical device (e.g., a stent) that has already been deployed inside a lumen (e.g., a body lumen).